scholarly journals Effect of ultrasound on drying kinetics of El Henna leaves (Lawsonia inermis)

2018 ◽  
Author(s):  
Said Bennaceur ◽  
Lyes Bennamoun ◽  
Antonio Mulet ◽  
Belkacem Draoui ◽  
Juan A. Cárcel
Keyword(s):  
Weibull Model ◽  
Process Variable ◽  
Experimental Models ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Drying Process ◽  
Lawsonia Inermis ◽  
Ultrasound Application ◽  
Kinetics Of ◽  
Best Fit

In this work the influence of some process variable on drying rate of henna leaves was studied. For this reason, henna leaves were dried (1 m/s) with and without ultrasound application at three temperatures, 40, 50 and 60 °C. As can be expected, the higher the temperature the faster the drying process. Ultrasound application increase drying rate at every temperature tested. Drying kinetics were modeled by using different experimental models. Weibull model provided the best fit for henna leaves drying kinetics. Keywords:Ultrasonic; Weibull model; henna leave;, temperature. 

Experimental Evaluation and Kinetic Analysis of Direct-Contact Ultrasonic Fabric Drying Process

2020 ◽  
Vol 13 (2) ◽  
Author(s):  
Chang Peng ◽  
Saeed Moghaddam
Keyword(s):  
Direct Contact ◽  
Ultrasonic Transducer ◽  
Gaussian Model ◽  
Weibull Model ◽  
Drying Kinetics ◽  
Energy Prices ◽  
Drying Process ◽  
Liquid Form ◽  
Drying Time ◽  
Kinetics Of

Abstract Over the past two decades, due to the rising energy prices and growing awareness about climate change, significant efforts have been devoted to reducing the energy consumption of various home appliances. However, the energy efficiency of clothes dryers has little improvement. Recent innovations in the direct-contact ultrasonic fabric drying technique offer new opportunities for energy saving. In this technique, high-frequency mechanical vibrations generated by the ultrasonic transducer are utilized to atomize water from a fabric in the liquid form, which demonstrates great potential for reducing energy use and drying time of the fabric drying process. Here, for the first time, fabric drying kinetics under different direct-contact ultrasonic drying conditions were investigated experimentally and analytically. The drying processes of four kinds of fabrics were experimentally tested under different ultrasonic transducer vibration frequency (115, 135, and 155 kHz) and input power (1.2, 2.5, and 4.4 W) conditions. According to the experimental data, five different kinds of models were applied to quantify the drying kinetics of fabrics during direct-contact ultrasonic drying. The models not only incorporated the transducer parameters but also the parameters related to the nature of fabric. Our evaluation results of model prediction performance demonstrated that the two empirical models, i.e., the Weibull model and the Gaussian model, were superior to the three semi-theoretical models for anticipating the drying kinetics of fabrics under direct-contact ultrasonic drying. Furthermore, the Weibull model is more suitable for practical energy-efficient direct-contact ultrasonic fabric drying applications compared with the Gaussian model.

scholarly journals Effect of blanching methods on drying kinetics of bell pepper

2011 ◽  
Vol 11 (48) ◽  
pp. 5457-5474
Author(s):  
Toyosi Tunde - Akintunde ◽  
◽  
BO Akintunde ◽  
A Fagbeja ◽  
◽  
...  
Keyword(s):  
Palm Oil ◽  
Water Movement ◽  
Drying Kinetics ◽  
Bell Pepper ◽  
Drying Rate ◽  
Drying Process ◽  
Oil Water ◽  
Drying Rates ◽  
Kinetics Of

Various blanching methods and drying temperatures were applied to bell pepper (Capiscum annum) to investigate the effect on its drying characteristics. Pepper (Capiscum annum) is an abundant and cheap source of vitamins, minerals and fibre. However, its high moisture content makes it susceptible to deterioration. The most common method of preservation is drying but the dried products obtained are of reduced nutritional qualities. Pretreatment of pepper before drying improves the quality of the dried pepper and increases its drying rate. Steam and water blanching as a form of pretreatment has been reported to increase drying rate and improve the quality of dried products but there is not much information on other types of oil/water blanching methods. The effect of blanching (steam, water, palm oil/water and groundnut oil/water) as a pretreatment on the drying kinetics of bell pepper dried at temperatures of 50, 60, 70, 80 and 90o C, was studied. Drying of raw untreated bell pepper was taken as a control. The results indicate that water removal at the initial stage of the drying process was highest and there was a rapid decrease as drying continued until equilibrium was reached at the end of process. The blanched samples generally had higher drying rates (at p<0.05) than the untreated samples. The values for the drying rate for steam and water blanched samples were higher (but not at p<0.05) than the drying rates for samples blanched in oil/water mixtures. The drying rate as well as effective moisture diffusivity, Deff, increased with increasing drying temperature. Values of Deff varied from 3.55 x 10-9 m 2/s to 2.34 x 10-9 m 2/s with the highest being SB (steam blanched) at 80oC and the lowest UB (unblanched) at 50oC. The drying process took place mainly in the falling rate period. The activation energies varied from 39.59 to 83.87 kJ/mol, with PB (palm oil/water blanched) samples having the lowest and UB having the highest Ea value. The lower values for pretreated samples imply that water movement from the internal regions is faster in pretreated samples. This suggests that blanching as a method of pretreatment generally increases water diffusion.

scholarly journals Drying kinetics and effective diffusion of buckwheat grains

2020 ◽  
Vol 44 ◽  
Author(s):  
Valdiney Cambuy Siqueira ◽  
Rafael Araújo Leite ◽  
Geraldo Acácio Mabasso ◽  
Elton Aparecido Siqueira Martins ◽  
Wellytton Darci Quequeto ◽  
...  
Keyword(s):  
Effective Diffusion ◽  
Information Criterion ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Linear Regression Method ◽  
Drying Process ◽  
Food Sector ◽  
Drying Time ◽  
Air Speed ◽  
Kinetics Of

ABSTRACT Buckwheat has become important in the food sector as its flour does not contain gluten. Since buckwheat is a relatively new crop in the agricultural environment, there is little information available regarding its processing. Drying is one of the most important post-harvest stages of buckwheat. The aim of the present study was to describe the drying process of buckwheat grains. Buckwheat grains with a moisture content of 0.41 ± 0.01 (dry basis, d.b.) were harvested, followed by drying in an experimental dryer at the temperatures of 40, 50, 60, 70, and 80 °C, at an air speed of 0.8 m s-1. The drying rate was determined, and the mathematical models generally employed to describe the drying process of several agricultural products were fitted to the experimentally obtained data. Model selection was based on the Gauss-Newton non-linear regression method and was complemented by Akaike Information Criterion and Schwarz’s Bayesian Information Criterion. It was concluded that the drying rate increased with an increase in temperature and decreased with an increase in drying time. It is recommended to use the Midilli model to represent the drying kinetics of buckwheat grains at the temperatures of 40, 60, and 70 °C, while the Approximation of diffusion model is recommended for the temperatures of 50 and 80 °C. The magnitudes of effective diffusion coefficients ranged from 1.8990 × 10-11 m2 s-1 to 17.8831 × 10-11 m2 s-1. The activation energy required to initiate the drying process was determined to be 49.75 kJ mol-1.

Drying Kinetics Evaluation of Solid Red Bricks

2015 ◽  
Vol 3 ◽  
pp. 119-134
Author(s):  
E. Barreira ◽  
J.M.P.Q. Delgado ◽  
V.P. de Freitas
Keyword(s):  
Moisture Content ◽  
Molecular Diffusion ◽  
Moisture Transfer ◽  
Drying Kinetics ◽  
Drying Process ◽  
Drying Time ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of ◽  
Best Fit

Moisture is one of the most deteriorating factors of buildings. The moisture content depends on hygroscopic equilibrium between buildings materials and environment, which is determined by the drying and wetting rate of masonry. So, the moisture content is not only determined by the water that is absorbed by the material, but also by the amount of water that is evaporated under favourable conditions, which is described by the drying process.This work presents the results of an experimental evaluation of the drying kinetics of solid red brick, considering the bulk moisture transfer. The drying kinetics was assessed considering different environment conditions (air temperature and humidity). The experimental results showed that the drying flux is extremely dependent of temperature and relative humidity in the first stage of the drying process. The values obtained were between 0.025 kg/m2h (T=15oC and RH=80%) and 0.135 kg/m2h (T=30oC and RH=50%), for the worst and better drying ambient conditions.Different first-order kinetics models, available in the literature, were adjusted to describe the drying process and estimate the equilibrium moisture content of the samples. The results point that Midilli et al. model allows the best fit and that the drying time constant is strongly affected by the drying air conditions. It was also estimated the apparent molecular diffusion coefficient for solid red brick samples and its variation with temperature.

scholarly journals Drying kinetics of mango fruit using tray and oven dryer

2020 ◽  
Vol 3 (2) ◽  
pp. 51
Author(s):  
Nurhasmanina Norhadi ◽  
Ammar Mohd Akhir ◽  
Nor Roslina Rosli ◽  
Farid Mulana
Keyword(s):  
Moisture Content ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Airflow Rate ◽  
Drying Process ◽  
Air Velocity ◽  
Mango Fruit ◽  
Drying Time ◽  
Different Temperatures ◽  
Kinetics Of

Drying is generally used to increase the shelf life of food products. In this context, mango fruit is used as a sample for the drying process because of its high commercial value and particularly high moisture content. The mango was sliced into few batches of sample with a size of 20 mm × 30 mm × 5 mm each. The experiments were conducted using tray and oven dryer at different temperatures of 40, 50 and 60 °C with a steady airflow rate of 1.3 m/s. The objectives are to study the effect of drying time, temperature and air velocity towards drying of mango fruit, to compare the physical characteristics of mango sample after drying and to determine the best drying kinetics model fitted to each tray and oven dryer. The results showed that the increase in drying time, temperature and air velocity would reduce the moisture content while at the same time, drying rate increased significantly. Tray dryer was found to be more effective than oven dryer because of higher drying rate with better product quality and appearance at the end. Furthermore, the gathered data were fitted into few widely used drying mathematical models and it was found that Henderson and Pabis model at 60°C is best suited for tray dryer whereas Page model at 40 °C is the best for oven dryer.

Study on the Drying Mechanism and Dynamics of Palygorskite

2011 ◽  
Vol 422 ◽  
pp. 501-504
Author(s):  
Jiang Quan Ma ◽  
Qing Ling Lu ◽  
Jun Hao Xia ◽  
Xiao Bin Gan ◽  
Chao Yao
Keyword(s):  
Activation Energy ◽  
Environmental Protection ◽  
Drying Kinetics ◽  
Diffusion Activation Energy ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Curves ◽  
Kinetics Of ◽  
Diffusion Activation

Palygorskite had large applications in chemical, environmental protection, medicine processes and so on. However, since the mineral limitations of natural palygorskite, both improving its quality and meeting the need of industry, palygorskite usually needs to be activated before using it. The influences of activation during the drying process were studied, as well as the drying kinetics of the non-activated of palygorskite. The results showed that the drying rate of palygorskite increased at first, and then came to a constant value, and kept that value for some time. After that, drying rate decreased with time going. Compared with drying curves of the non activated palygorskite, the samples made some changes after activation. The drying process of non activated palygorskite could be described as the equation of MR=exp(-ktn). The diffusion activation energy (E) of non activated palygorskite was equal to 17.14kJ•mol-1, former factors of Arrhenius was equal to 4.19×10-5 m2•s-1.

Study on the Drying Mechanism and Dynamics of Palygorskite

2013 ◽  
Vol 706-708 ◽  
pp. 456-459
Author(s):  
Shi Long Wang ◽  
Li Na Wang
Keyword(s):  
Activation Energy ◽  
Environmental Protection ◽  
Drying Kinetics ◽  
Diffusion Activation Energy ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Curves ◽  
Kinetics Of ◽  
Diffusion Activation

Palygorskite had large applications in chemical, environmental protection, medicine processes and so on. However, since the mineral limitations of natural palygorskite, both improving its quality and meeting the need of industry, palygorskite usually needs to be activated before using it. The influences of activation during the drying process were studied, as well as the drying kinetics of the non-activated of palygorskite. The results showed that the drying rate of palygorskite increased at first，and then came to a constant value, and kept that value for some time. After that, drying rate decreased with time going. Compared with drying curves of the non activated palygorskite, the samples made some changes after activation. The drying process of non activated palygorskite could be described as the equation of MR=exp(-ktn).The diffusion activation energy (E) of non activated palygorskite was equal to 17.14kJ.mol-1, former factors of Arrhenius was equal to 4.19×10-5 m2.s-1.

Mathematical Modeling of Thin-Layer Solar Drying for Yarrow, Coriander and Hollyhock

2015 ◽  
Vol 11 (5) ◽  
pp. 691-700 ◽  
Author(s):  
Yasaman Amanlou ◽  
Teymour Tavakoli Hashjin ◽  
Barat Ghobadian ◽  
Gholamhassan Najafi
Keyword(s):  
Theoretical Models ◽  
Drying Kinetics ◽  
Medicinal Products ◽  
Drying Process ◽  
Chi Square ◽  
Air Temperatures ◽  
C 50 ◽  
Drying Conditions ◽  
Kinetics Of ◽  
Best Fit

Abstract The objective of this study is to investigate the drying kinetics of Yarrow, Coriander and Hollyhock flowers. These three medicinal products were dried using a solar hybrid photovoltaic-thermal dryer. The drying process was examined at the air temperatures of 40°C, 50°C and 60°C and air velocities of 0.5, 1 and 1.5 m/s. The experimental drying data were fitted to different theoretical models to predict the drying kinetics. Nonlinear regression analysis was performed to relate the parameters of the model with the drying conditions. The performance of these models was evaluated by comparing the correlation coefficient ($${R^2}$$), root mean square error (RMSE) and the chi-square ($${\chi ^2}$$) between the observed and the predicted moisture ratios. Among all the models, the exponential two-term was found to have the best fit in this study. Also the influence of plant type, air temperature and velocity was investigated.

scholarly journals The kinetics of nutritional quality changes during winter jujube slices drying process

2021 ◽  
Vol 13 (1) ◽  
pp. 73-82
Author(s):  
Yubao Niu ◽  
Shiyu Wei ◽  
Huan Liu ◽  
Yongzhen Zang ◽  
Yuxue Cao ◽  
...  
Keyword(s):  
Degradation Kinetics ◽  
Weibull Model ◽  
Reducing Sugar ◽  
Total Acidity ◽  
Drying Process ◽  
Drying Time ◽  
Nutrient Quality ◽  
Air Impingement ◽  
Weibull Models ◽  
Kinetics Of

The purpose of this research is to investigate the kinetics of nutrient quality (Vitamin C (Vc), reducing sugar and total acidity) change of winter jujube slices that under different drying temperatures (55, 60, 65 and 70?) and different air velocities (3, 6 and 9m/s) during the air-impingement drying process. Results showed that the content of Vc, reducing sugar and total acidity decreased with increasing drying time. Furthermore, analysis of variances indicated that the drying temperature, air velocity and time had a significant effect on the loss of Vc, reducing sugar and total acidity (p<0.05). Zero order, first order and Weibull models were used to fit the experimental data, Weibull model was considered as the most suitable one to the degradation kinetics of Vc, reducing sugar and total acidity in dried samples at different temperatures and air velocities. According to the Arrhenius formula, the activation energy of Vc, reducing sugar and total acidity degradation kinetics were 63.78 kJ/mol, 36.48 kJ/mol and 153.51 kJ/mol, respectively. This research can provide some references for enhancing dried products quality in the jujube drying industry.

scholarly journals Mathematical modeling of pequi pulp drying and effective diffusivity determination

2017 ◽  
Vol 21 (7) ◽  
pp. 493-498 ◽  
Author(s):  
Elisabete P. de Sousa ◽  
Rossana M. F. de Figueirêdo ◽  
Josivanda P. Gomes ◽  
Alexandre J. de M. Queiroz ◽  
Deise S. de Castro ◽  
...  
Keyword(s):  
Experimental Data ◽  
Effective Diffusivity ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Drying Time ◽  
Air Speed ◽  
Drying Curves ◽  
Increasing Temperature ◽  
Kinetics Of ◽  
Best Fit

ABSTRACT The aim of this work was to study the drying kinetics of pequi pulp by convective drying at different conditions of temperature (50, 60, 70 and 80 °C) and thickness (0.5, 1.0 and 1.5 cm) at the air speed of 1.0 m s-1, with no addition of adjuvant. The experimental data of pequi pulp drying kinetics were used to plot drying curves and fitted to the models: Midilli, Page, Henderson & Pabis and Newton. Effective diffusivity was calculated using the Fick’s diffusion model for a flat plate. It was found that, with increasing thickness, the drying time increased and, with increasing temperature, the drying time was reduced. The Midilli model showed the best fit to the experimental data of pequi pulp drying at all temperatures and thicknesses, presenting higher coefficients of determination (R2), indicating that this model satisfactorily represents the pequi pulp drying phenomenon. There was a trend of increase in the effective diffusivity with the increase in pulp layer thickness and temperature.

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